1. Field of the Invention
The invention relates to packaging and unpackaging envelopes.
In the present text, the term “envelopes” is used to mean any paper or even cardboard bags designed to receive letters, sheets of paper, or any other article that might be contained therein. In general, an envelope is considered to be a “flat item”, a term that is in frequent use. This applies herein, the envelope having a certain amount of flexibility, depending on how it is structured, such flexibility giving rise, in particular under stress, to deformation due to differences in thickness that exist at different places of each envelope.
2. Description of the Prior Art
FR-A-2 837 793 discloses a packaged block of envelopes that offers improved stability and/or improved surface evenness compared with solutions prior to that solution. For that purpose, that packaged block of envelopes comprises:                a series of folded envelopes, each of which has a front face onto which a closure flap for closing the envelope is folded over, a back face, and a periphery, the envelopes being disposed face against face, each face of each envelope having first, second, third, and fourth corners, and the closure flap having a thickness and being suitable for being folded over along an edge of the folded envelope that interconnects the first and second corners;        rigid retaining plates disposed on either side of said series of envelopes, one plate facing one of the faces, namely the front face or the back face, of the first envelope in the series, and the other plate facing the other face of the last envelope in the series; and        holding means for holding the series of envelopes together, said holding means surrounding the series of envelopes and the two retaining plates tightly.        
Those retaining plates are preferably uninterrupted, plane, and smooth, each plate being provided with two vertical side grooves that are open to receive spacer rods, making it possible to remove the blocks of envelops without breaking (or indeed removing) the holding means which are advantageously elastically deformable and which surround the series of envelopes and the retaining plates in an elastic state.
FR-A-2 837 793 also discloses a set comprising:                a series of packaged blocks of envelopes as presented above;        a goods-handling pallet on which a plurality of blocks of envelopes stand, at least some of the blocks being disposed so that each of the envelopes stands on a segment of its periphery, and on which rigid retaining plates stand for retaining said blocks facing a top bearing surface of the pallet; and        wrapping means for wrapping the pallet and the series of envelopes disposed on it, those wrapping means comprising an elastic stretch film stretched in its elastic deformation zone.        